**********************************************************************
*** Delta C-13 values (per mil) derived from CO2 in flask air      ***
*** samples collected at Mauna Loa, Hawaii                         ***
*** Source: C. E. Allison                                          ***
***              R. J. Francey                                     ***
***              P. B. Krummel                                     ***  
***              Atmospheric, Research, Commonwealth Scientific,   ***
***              And Industrial Research Organisation,             ***
***              Aspendale, Victoria,                              *** 
***              Australia  3195                                   ***                   
***                                                                ***   
*** September 2003                                                 ***
***                                                                ***
**********************************************************************

	Jan. 	Feb.	Mar.	Apr.	May	Jun.	Jul.	Aug.	Sep.	Oct.	Nov.	Dec.	Ann.  Ave.

1991			-7.874	-7.998	-8.052	-8.026	-7.921	-7.793	-7.7	-7.689	-7.764	-7.833	
1992	-7.869	-7.945	-8.039	-8.06	-8.052	-8.002	-7.885	-7.794	-7.717	-7.686	-7.744	-7.828	-7.885
1993	-7.866	-7.879	-7.904	-7.934	-7.963	-7.939	-7.843	-7.722	-7.664	-7.692	-7.772	-7.846	-7.835
1994	-7.85	-7.85	-7.916	-7.986	-8.016	-8	-7.926	-7.815	-7.726	-7.732	-7.802	-7.864	-7.874
1995	-7.9	-7.968	-8.05	-8.073	-8.101	-8.04	-7.904	-7.894	-7.874	-7.815	-7.843	-7.88	-7.945
1996	-7.905	-7.976	-8.039	-8.053	-8.071	-8.051	-7.948	-7.846	-7.785	-7.776	-7.827	-7.901	-7.932
1997	-7.945	-7.961	-8.026	-8.112	-8.122	-8.051	-7.943	-7.843	-7.752	-7.763	-7.892	-7.962	-7.948
1998	-7.983	-8.056	-8.147	-8.208	-8.211	-8.132	-8.025	-7.941	-7.864	-7.864	-7.956	-8.03	-8.035
1999	-8.026	-8.034	-8.133	-8.202	-8.161	-8.118	-8.063	-7.959	-7.879	-7.877	-7.945	-8.006	-8.034
2000	-8.048	-8.109	-8.168	-8.167	-8.147	-8.124	-8.046	-7.952	-7.883	-7.9	-7.975	-8.01	-8.044
2001	-8.041	-8.103	-8.18	-8.231	-8.219	-8.141	-8.026	-7.928	-7.858	-7.873	-7.973	-8.035	-8.051


Monthly values (per mil) are reported on the international VPDB-CO2 scale. Monthly values were 
calculated as the mean of the daily values from a smooth curve fit to the data using the curve-
fitting routines described by Thoning et al., 1989 (J. Geophys Res. 94, 8549-8565).  Annual 
values are the arithmetic means of the 12 monthly values.